April is the turning point in New Zealand's temperate garden: frost risk officially begins this month (the temperate zone's frost period runs April through November), and garlic's sowing window opens for the first time all year. At the same time, a cluster of summer crops — basil, courgette, cucumber, spinach, tomato and yacon — are harvesting through their final month before the window closes, while Jerusalem artichoke's harvest is only just getting started.
The NZ Temperate April Growing Context
Soil is still holding some warmth from summer, but nights are noticeably colder and the first light frosts can arrive by month's end. That combination makes April a month of two jobs at once: getting garlic and root crops in while the ground is workable, and getting the last value out of frost-tender crops before a cold night ends them.
Typical April conditions in temperate gardens:
- First frosts possible from this month onward
- Cooling, shortening days slowing growth generally
- Soil still workable for planting garlic cloves
- A wide harvest as summer crops finish and autumn roots continue
- Last chance to use frost-tender crops before losing them
What to Sow This Month
Garlic
Garlic's sowing window runs April through May in the temperate zone — this is the first month it opens all year, so it's the main sowing job in April. Plant individual cloves 5cm deep and 15cm apart; expect roughly seven months to harvest, which lands in November–December.
Cultivar picks: Rocombole Early Red (Koanga Institute), planted on 10–12.5cm diagonal spacings into soil enriched with well-rotted manure or compost; or Elephant (Koanga Institute) for larger cloves, planted 15cm apart on the diagonal, with flower heads removed while young to encourage bulb size.
Beetroot
Beetroot's window runs August through May, so April is well within range. Direct sow and thin seedlings to about 10cm apart — beetroot doesn't transplant well, so don't raise it in trays. It tolerates light frost, which is useful now that the frost period has started.
Cultivar pick: Bulls Blood (Kings Seeds NZ) — suited to autumn sowing, with deep red foliage as a bonus.
Carrot
Carrot's sowing window runs September through May. Direct sow only — carrots don't transplant — and keep the seedbed evenly moist until germination, which matters more in April as evaporation slows but soil can still crust.
Cultivar picks: Amsterdam Sprint (Kings Seeds NZ) for a fast, reliable crop; Akaroa Long Red (Koanga Institute) if your soil is deep and loose enough for a heritage long-rooted type.
Silverbeet
Silverbeet's window runs August through May, making it one of the few crops that will carry a garden through winter once established. Direct sow, or raise in trays if you'd rather transplant into gaps left by finished summer crops.
Cultivar picks: Ford Hook Giant (Kings Seeds NZ) for a heavy-cropping standard, direct sown; Bright Yellow (Kings Seeds NZ), raised as transplants, for colour as well as flavour.
Not yet: Broccoli and Kale
Both are on gardeners' minds by April, but their sowing windows don't open until August in the temperate zone. Lettuce's sowing window has also just closed at the end of March — the next chance to sow it is spring. Hold off on all three rather than sowing early.
What to Harvest This Month
April brings the last of several summer crops alongside the ongoing autumn roots:
- Basil, courgette, cucumber, spinach, tomato and yacon — all close out their harvest windows this month. Pick or dig everything usable before the first frost puts an end to them.
- Beans (climbing) and peas — both harvest through to May; keep picking.
- Beetroot, carrot and silverbeet — well within their long harvest windows and unaffected by the first frosts.
- Pumpkin — harvest window runs through June; leave until the skin resists a thumbnail, then cure in the sun before storing.
- Jerusalem Artichoke — harvest window opens this month, the opposite of everything else on this list: frost is what kicks it off rather than ending it, and it'll keep going right through winter.
Garden Jobs for April
Clear space for garlic
Garlic is going in now, so use any bed vacated by finished summer crops and work in compost ahead of planting rather than leaving soil prep until the day you plant.
Watch for the first frost
Once frosts start, basil, courgette, cucumber, tomato and yacon are finished for the season. Harvest or dig everything usable ahead of a forecast cold night rather than losing the last of the crop overnight.
Keep autumn roots and greens moving
Beetroot, carrot and silverbeet are all mid-harvest — keep picking and thinning so remaining roots and leaves have room to size up through the cooler weeks ahead.
Common April Mistakes
Planting garlic too shallow or too close
Cloves need to go in at 5cm deep and roughly 15cm apart. Shallow planting or crowding produces smaller bulbs at harvest.
Losing frost-tender crops to an unexpected frost
Basil, courgette, cucumber, tomato and yacon all end their harvest window in April, and an early frost can take them out before you've picked or dug everything. Check forecasts and harvest ahead of a cold night.
Sowing broccoli, kale or lettuce too early
Broccoli and kale don't open until August, and lettuce's window closed at the end of March. Getting ahead of the data here doesn't gain time — it just risks a poor stand.
Looking Ahead
May closes out the sowing windows for beetroot, carrot and silverbeet, and frost risk deepens as the temperate zone moves toward winter. Garlic planted this month will be establishing roots through the cooler soil ahead of winter dormancy — exactly the timing it needs. Jerusalem artichoke's harvest, just opened this month, will keep running right through to August.
Ready for next month? See *What to Plant in NZ Temperate in May*, or explore the full NZ Temperate Planting Calendar →.